1. Field of the Invention
The present invention relates to a thermosetting, solventless, liquid heat-resistant resin composition, high in storage stability and excellent in workability.
2. Description of the Related Art
Recently, various materials are used under severer conditions in electrical and electronic equipments as well as in mechanical equipments. Naturally, severer demands are directed to the heat-resisting property of a resin component used as, for example, an adhesive.
Aminobismaleimide, which is an addition reaction product between N,N'-bismaleimide and diamine, is known as such a heat-resistant resin. The known heat-resistant resin noted above, however, is defective in that a long heat treatment at high temperatures is required for the curing. To overcome the defect, various measures have been proposed to date. For example, it is proposed to add an epoxy resin in order to improve the curing property, adhesive property, etc. of aminobismaleimide, though the heat-resisting property of aminobismaleimide may be somewhat impaired by the epoxy resin addition.
It is also proposed to subject polymaleimide, polyamine and epoxy resin to a solution reaction or a bulk reaction, followed by dissolving the reaction product in a solvent. The resultant resin is certainly excellent in viscosity stability at a low temperature, e.g., 5.degree. C. However, where the resultant resin is cured after storage over a long period of time, the resin fails to exhibit an initial strength in the heating step, making it necessary to preserve the resin under very low temperatures or under a B stage (semi-curing). Further, it is very difficult to make the above-noted three components solventless.